Measurements in Circular Wave Tank With Active Generators

2009 ◽  
Author(s):  
Joao Alcino de Andrade Martins
Keyword(s):  
Wave Field ◽  
New Technology ◽  
Experimental Results ◽  
New Wave ◽  
Force Measurements ◽  
Ocean Engineering ◽  
Wave Tank ◽  
Irregular Wave ◽  
Testing Tank

This paper discusses some aspects of the new technology in testing tank for Naval and Ocean Engineering developed at NAOE-Osaka University, Japan, based on the concept of active wavemakers all around the tank perimeter [1]. Past and present measurements shown that the wave field is homogeneous with some restrictions and can keep irregular wave more than 50 wave periods. The experimental results for platform model diffraction force are good and agree with theory and also with early tests [7]. The analyses of wave and platform model force measurements prove the new wave tank concept precision, usefulness and reliability.

scholarly journals Loop-Type Wave-Generation Method for Generating Wind Waves under Long-Fetch Conditions

2017 ◽  
Vol 34 (10) ◽  
pp. 2129-2139 ◽  
Author(s):  
Naohisa Takagaki ◽  
Satoru Komori ◽  
Mizuki Ishida ◽  
Koji Iwano ◽  
Ryoichi Kurose ◽  
...  
Keyword(s):  
Wind Wave ◽  
Wind Waves ◽  
Peak Frequency ◽  
Wave Generation ◽  
New Wave ◽  
Wave Tank ◽  
Irregular Wave ◽  
Wind Speeds ◽  
Type Wave ◽  
Wave Generator

AbstractIt is important to develop a wave-generation method for extending the fetch in laboratory experiments, because previous laboratory studies were limited to the fetch shorter than several dozen meters. A new wave-generation method is proposed for generating wind waves under long-fetch conditions in a wind-wave tank, using a programmable irregular-wave generator. This new method is named a loop-type wave-generation method (LTWGM), because the waves with wave characteristics close to the wind waves measured at the end of the tank are reproduced at the entrance of the tank by the programmable irregular-wave generator and the mechanical wave generation is repeated at the entrance in order to increase the fetch. Water-level fluctuation is measured at both normal and extremely high wind speeds using resistance-type wave gauges. The results show that, at both wind speeds, LTWGM can produce wind waves with long fetches exceeding the length of the wind-wave tank. It is observed that the spectrum of wind waves with a long fetch reproduced by a wave generator is consistent with that of pure wind-driven waves without a wave generator. The fetch laws between the significant wave height and the peak frequency are also confirmed for the wind waves under long-fetch conditions. This implies that the ideal wind waves under long-fetch conditions can be reproduced using LTWGM with the programmable irregular-wave generator.

Pond Treatment of Rettery Wastewaters

1987 ◽  
Vol 19 (12) ◽  
pp. 79-83
Author(s):  
K. Bartoszewski ◽  
A. Bilyk
Keyword(s):  
Activated Sludge ◽  
Treatment Process ◽  
New Technology ◽  
Treatment Plant ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Experimental Results ◽  
Aerobic Conditions ◽  
Aerobic Stabilization ◽  
In Series

Rettery wastewaters were treated in anaerobic and aerobic ponds. Anaerobic treatment yielded efficiencies of BOD5 and COD removal as low as 20%. The treatment process conducted under aerobic conditions in aerated and stabilizing ponds arranged in series took from 18 to 20 days and gave efficiencies of BOD5 and COD removal amounting to 90%. The experimental results were interpreted by virtue of the Eckenfelder equation. Excess activated sludge was subjected to aerobic stabilization in a separate tank. A new technology was suggested for the existing obsolete industrial treatment plant.

Alternative Methodologies for Subsea Flexible Strength Analysis

2018 ◽  
Author(s):  
Anskey A. Miranda ◽  
Fred P. Turner ◽  
Nigel Barltrop
Keyword(s):  
Real World ◽  
Wave Train ◽  
Irregular Waves ◽  
Wave Crest ◽  
Strength Analysis ◽  
New Wave ◽  
Regular Wave ◽  
Wave Analysis ◽  
Sea State ◽  
Irregular Wave

This paper presents a study of the analysis methodologies used to predict the most likely response of flexibles in a subsea environment, with the aim of determining an efficient and reliable prediction methodology. The most accurate method involves simulating multiple wave realisations of a real world sea state, i.e. irregular waves, and post-processing the results to determine the most probable maximum (MPM). Due to the computationally intensive nature of this approach, however, regular wave analysis is typically used to determine flexible response. This approach considers the maximum wave within a design storm at a desired period; the choice of periods may leave room for uncertainty in the conservatism of the approach. With proper screening, regular wave analysis can be a valid yet overly conservative approach resulting in over design and additional cost. However, if screened incorrectly, there is a possibility that the choice of periods could give results that are under conservative. In addition to regular wave analysis, the paper presents two alternative methodologies to determine the most likely response, with the focus on reducing the computational resources required. The first alternative is an ‘Irregular Wave Screen’ approach in which the wave train is screened at areas of interest for waves within a user defined threshold of the maximum wave height, in addition to other user defined parameters. Only waves within these parameters are simulated to determine responses. The second alternative is the ‘New Wave’ approach, which models the most probable wave elevation around the maximum wave crest. The calculated new wave is then placed at the desired location to determine responses. The responses of the Regular, Irregular Wave Screen and New Wave methodologies are compared with the Irregular MPM approach to determine their feasibility to predict the response of flexibles in a real world irregular sea state with lower computational requirements.

Feeding Mathematical Modeling of Superalloy Vacuum-Electromagnetic Casting and its Application

2012 ◽  
Vol 629 ◽  
pp. 171-175
Author(s):  
Wen Zhong Jin ◽  
Su Fang Li ◽  
Wei Zhang
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
New Technology ◽  
Experimental Results ◽  
Electromagnetic Stirring ◽  
Shrinkage Cavity ◽  
Vacuum Casting ◽  
Electromagnetic Casting ◽  
Wide Range

The new technology of superalloy vacuum-electromagnetic casting was developed and the feeding mathematical model melt in vacuum-electromagnetic casting was established. The availability of mathematical model was approved by the experiments of the IN100 superalloy. The experimental results indicate that the feeding capacity of melt in vacuum casting can be greatly increased by imposing the 50Hz, 60A rotating electromagnetic stirring, which can decrease the central shrinkage cavity in superalloy ingots, so the quality of the superalloy ingots can be wide-range improved.

Predicted wave field in a laboratory wave basin

1990 ◽  
Vol 17 (6) ◽  
pp. 1005-1014 ◽  
Author(s):  
Michael Isaacson ◽  
Shiqin Qu
Keyword(s):  
Wave Field ◽  
Wave Diffraction ◽  
Diffraction Theory ◽  
Ocean Engineering ◽  
Laboratory Facilities ◽  
Rectangular Basin ◽  
Diffraction Wave ◽  
Wave Basin ◽  
Wave Generator ◽  
Reflection Boundary

The present paper describes a numerical method for predicting the wave field produced by a segmented wave generator undergoing specified motions in a wave basin which may contain partially reflecting sides. The approach used is based on linear diffraction theory and utilizes a point source representation of the generator segments and any reflecting walls that are present. The method involves the application of a partial reflection boundary condition, which is discussed. Numerical results are presented for the propagating wave field due to specified wave generator motions in a rectangular basin. Cases that are considered include both perfectly absorbing and partially reflecting beaches along the basin sides, as well as the presence of perfectly reflecting short sidewalls near the generator. The method appears able to account adequately for the effects of wave diffraction and partial reflections, and to predict the generated wave field realistically. Key words: coastal engineering, hydrodynamics, laboratory facilities, ocean engineering, wave diffraction, wave generation, wave reflection.

In Situ Burning Wave Tank Tests at Prudhoe Bay, Alaska1

1999 ◽  
Vol 1999 (1) ◽  
pp. 1269-1272
Author(s):  
Ian Buist ◽  
James McCourt ◽  
Joseph V. Mullin ◽  
Nick W. Glover ◽  
Charlene Hutton ◽  
...  
Keyword(s):  
Open Water ◽  
North Slope ◽  
Experimental Program ◽  
New Wave ◽  
Wave Tank ◽  
Burning Wave ◽  
Surface Active ◽  
Prudhoe Bay ◽  
And Training

ABSTRACT A series of research burns was carried out in the fall of 1997 in Prudhoe Bay, Alaska, in a new wave tank purpose-built for oil spill research and training. These tests were the culmination of a 3-year research project by Alaska Clean Seas (ACS) and S.L. Ross into the effects of oil type, emulsification, temperature and waves on in situ burning in Arctic open water conditions. The 1997 experimental program involved conducting mid-scale burns with fresh and weathered Alaska North Slope (ANS) and Milne Pt. crude oils and emulsion slicks in waves, including tests involving the addition of emulsion breakers. Emulsion breakers are surface active chemicals which are added at very low dosages (1:500 to 1:5000) to petroleum emulsions to promote separation of the emulsion into discrete oil and water phases.

Experimental Study on Deck-Temperature-Rising Technology in Different Deck Area

2012 ◽  
Vol 591-593 ◽  
pp. 2006-2010
Author(s):  
Cong Wei Xie ◽  
Wei Chi
Keyword(s):  
Experimental Study ◽  
Initial Temperature ◽  
New Technology ◽  
Experimental Results ◽  
Experimental Device

Deck-temperature-rising technology is the new technology that solves the antifreeze and deicing problems of ship deck. In this paper, the special experimental device was designed, and the influence laws of this new technology in different deck area were studied. Comparative experiments were done with the deck area at 18*22cm2, 26*22cm2 and 32*22cm2. The experimental results show that with the same initial temperature of water and deck surface, the deck area has significant impact on this new technology. The larger the deck area is, the greater the warming amplitude and the better warming effect can be achieved. For example, the warming amplitude is about 1.7°C as the deck area is 32*22cm2, while the warming amplitude is only about 0.6°C as the deck area is 18*22cm2. This conclusion will be valuable in further studies on this new technology.

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